CodeX App Creation Week 5


Welcome, welcome, bienvenido! I hope you had an amazing Thanksgiving with your family and friends! Are you excited that there is only one more week until winter break?

I know I am! School has been hard for me this semester, but I have had a lot of fun. I hope it has been fun for you as well. Let me know something special that has happened to you since September on Slack!

I will be on this time <.> Sry I missed you :(

Here is something special that happened to me,

I met Stephen Hawking! Do you know who he is?

Stephen Hawking is a world renowned physicist, cosmologist, and author. He studies blackholes in outer-space. He recently came to Harvard to talk about how blackholes can possibly be tunnels to other universes we do not know about.

I got the chance to speak to him. He is actually very funny and incredibly smart. I told him about the CodeX program. He said Hello


Here is a link to his website!


In case you wanted to know more about Stephen Hawking, here is a trailer about the recent Oscar-winning movie that was made on his life. It's called The Theory of Everything A MUST WATCH!!!! 

Alright, so today we are going to do TWO Things. Dos cosas :)

  1. We are going to give you more time to work on your Ball Bounce app.

  2. Allow you to form groups for our app challenge (more details during winter break!)

Now I know some of you have already finished the lesson, and that's great! But we want you to continue to add to it. The more you try adding different features and spend time being creative with the App Inventor, the better off you will be when our app competition begins.

LeT’s GeT iT cRaCkIn’

For the next 30-45 minutes, please continue to work on the ball bounce app.

Below are details that:

  1. Describe how to make the app (in case you did not finish)

  2. Describe how to add more features to your app (if you already finished) - Located at the very bottom of the page

If you have other ideas, please explore them! This is your opportunity to get creative :)

Ball Bounce App Creation- Overview

Does this look familiar? Have you ever seen something like this?

Today we are going to learn how this works (making an image bounce). Think about all the apps on your phone that you have used that involved some type bouncing and jumping on a screen. I bet most of the games you play on your phone involve this in one way or another!


Open the MIT App Inventor! And login using your credentials

Here is the link:

AND create a new project called “BallBounce”

Fill Parent

So like with our Doodle App, drag the Canvas over and FILL PARENT!

Now that we have a Canvas in place, we can add a “Ball Sprite.” This can also be found in the “Drawing and Animation” section in the Palette

Drag out a Ball component and drop it onto the Canvas.

PS To make the ball bigger and smaller by changing the Radius property in the Properties pane. TRY IT OUT!


Now Go to Blocks!

Choose the block when Ball1.Flung and drag-and-drop it onto the workspace. 

Flung refers to the user making a "Fling Gesture" with his/her finger to "fling" the ball. Fling is a gesture like what a golf club does, not like how you launch Angry Birds! In App Inventor, the event handler for that type of gesture is called when Flung.


Open the Ball drawer and scroll down in the list of blocks to get the set Ball1.Heading and set Ball1.Speed blocks


Mouse over the "speed" parameter of the when Ball1.Flung event handler. The get and set blocks for the speed of the fling will pop up. Grab the get speed block and plug that into the set Ball1.Speed block.

Do the same for the Ball's heading. Mouse over the heading parameter and you'll see the get heading block appear. Grab that block, and click it into the set Ball1.Heading block.


Now there is a logical explanation to this, don't freak out:

Set Ball1 Speed: You want to tell the app that when you "fling" the ball, you want it pick up speed

Set Ball1 Heading:  This tell the app the direction in which the ball is move towards based on how you "fling" the ball. 

Screen Shot 2016-11-18 at 4.54.29 PM.png

No it is important to ensure that the ball bounces off the edges!

Why do you think this is important? What would happen if we did not add this portion of code?


Take out an Android Phone (or find someone with one- sorry an iPhone will not work

  1. Click App (provide QR code for .apk)

  2. Then scan the QR Code with your phone!

FYI: If your phone does not have a QR Code Scanner, you can download one for free from the Google Play Store!

Now, in case you are an overachiever, which we hope you are:

Try adding these elements to your app:

  • Change the color of the ball based on how fast it is moving or which edge it reaches.

  • Scale the speed of the ball so that it slows down and stops after it gets flung.

  • Give the ball obstacles or targets to hit

  • Introduce a paddle for intercepting the ball, like a Pong game